Polychromophoric benzotriazole ultraviolet stabilizers for organic compositions

ABSTRACT

The invention relates to polychromophoric compounds which have been found to be effective ultraviolet stabilizers. The invention also relates to ultraviolet degradable organic compositions containing a stabilizing amount of the polychromophoric composition to prevent such degradation. These stabilizers are effective in the presence of other additives commonly employed in polymeric compositions including, for example, pigments, colorants, fillers, reinforcing agents and the like. These ultraviolet stabilizers may also be incorporated into the organic compositions in the polymer melt or dissolved in the polymer dope, coated on the exterior of the molded article, film or extruded fiber.

This invention relates to polychromophoric ultraviolet stabilizers andtheir use in organic compositions. More particularly, the inventionrelates to polychromophoric compositions and the stabilization ofultraviolet degradable organic compositions against deteriorationresulting from the exposure to such radiations with suchpolychromophoric compositions.

The degradative effects of ultraviolet light on various organiccompositions is well known in the art. The photo-deterioration ordegradation is of particular concern with organic photo-degradablecompositions which are exposed to untraviolet light, such as sunlight,for long periods of time. One group of such photo-degradable organiccompositions are polymeric compositions such as polyolefins, polyestersand the like. On exposure to sunlight for extended periods of time,these polymeric compositions degrade and their physical properties arereduced to render the polymeric composition less useful for mostapplications. Therefore, considerable effort has been directed toproviding a solution to the photo-degradation problem of polymericcompositions. As a result of this effort, there have been discoveredmany additives and stabilizers which improve the stability of polymericcompositions.

Moreover, various additives and stabilizers exhibit the power to absorbultraviolet radiation within the band of 2900 to 4000 A. and, whenincorporated in various plastic materials such as transparent sheets,the resultant sheet acts as a filter for all the radiation passingthrough and will transmit only such radiations as are not absorbed bythe sheet and/or the absorbing agent. It is thus possible to screen outundesirable radiations and utilize the resulting transparent sheet as afilter in many technical and commercial applications, such as wrappingsfor food products and the like.

While there are many additives, stabilizers and mixtures thereof whichare known in the art to improve the ultraviolet light stability oforganic compositions, there is a need in the art for more efficient andeffective stabilizers to prevent the photo-degradation of organiccompositions susceptible to photo-degradation. Therefore, to provide amore effective and efficient ultraviolet stabilizer for organiccompositions susceptible to such degradation would be an advance in thestate of the art.

It is, therefore, an object of the present invention to provide moreeffective and efficient ultraviolet light stabilizer compositions.

Another object of the present invention is to provide usefulcompositions characterized by improved resistance to ultravioletdegradation and deterioration.

It is still another object of the present invention to providecompositions containing polychromophoric compositions which areresistant to ultraviolet degradation.

It is a still further object of this invention to provide processes forimproving the resistance of organic materials to deterioration anddegradation by actinic radiation and especially ultraviolet radiation.

It is a still further object of this invention to provide compositionsand processes for improving the resistance of organic materials todeterioration and degradation by actinic radiations, including shortwave-length visible radiations.

Further objects and advantages of the invention will be apparent tothose skilled in the art from the accompanying disclosure and claims.

In accordance with the present invention, polychromophoric compositionsare provided which are useful as ultraviolet stabilizers or ultravioletscreening agents. These organic compositions contain at least oneheterocyclic group containing composition connected through a carboxylgroup to an aromatic ring which, upon exposure to ultraviolet light, mayundergo the "photo-Fries" rearrangement. The polychromophoriccompositions of the present invention have the following structure:

    (A).sub.x C

wherein A is a group having the structure ##SPC1##

wherein

R₁, R₂, R₃ and R₄ are hydrogen, lower alkyl or substituted lower alkylhaving 1 to 12 carbon atoms, cycloalkyl, substituted cycloalkyl, aryl orsubstituted aryl having 6 to 18 carbon atoms, lower alkylaryl,aryl-substituted-aryl, chloro, bromo, fluoro, alkoxy and substitutedalkoxy containing 1 to 12 carbon atoms, aryloxy, disubstituted amino,cyano, carboalkoxy and the substituents R₁, R₂ and R₃, and R₃ and R₄,combined with the carbon atoms to which they are attached, are joinedalkylene groups completing a carbocyclic ring, which ring can also besubstituted with one or more of the substituents listed above for R₁,R₂, R₃ and R₄.

I is a substituent listed above for R₁, R₂, R₃ and R₄ and is present onall positions of the benzenoid ring, except the carbon atom attached tothe N substituent and the carbon atom attached to the carbonyl group.The carbonyl connecting group is attached to the benzenoid ring in theortho, meta or para position from the carbon atom connected to theheterocyclic ring. At least one I attached to a carbon atom adjacent tothe carbon atom attached to the carbonyl group is hydrogen. The other Isubstituents can all be one of the substituents listed above ordifferent listed substituents; x is an integer of 1 to 6, preferably 1to 3;

C is an aromatic moiety having the formula ##SPC2##

I is the same substituent as listed above and is present in allpositions of the benzenoid ring except the carbon atom attached to thecarbonyl group connecting the A and C moieties. The A moiety is attachedto the benzenoid ring in from 1 to 6 positions. If two A moieties areattached to the C moiety they can be attached in the ortho, meta or paraposition from each other. If three or four A moieties are attached tothe C moiety they can be attached in the ortho or meta positions fromeach other. It is necessary that at least one I substituent to thecarbon atom attached to the carbonyl group be hydrogen so that, onexposure to ultraviolet light, the aryl ester of heterocyclic aromaticacid is capable by the photo-Fries rearrangement of forming a phenolgroup in that position formerly joined through an oxygen atom to thecarbonyl linking group. The remaining I substituent can all be one ofthe substituents listed above or different listed substituents.

Suitable heterocyclic A groups having the structure ##SPC3##

are for example substituted and unsubstituted benzotriazoles such as4-(5-chloro-2H-benzotriazol-2-yl)phenoxycarbonyl,4-(2H-benzotriazol-2-yl)phenoxycarbonyl,4-(5-methoxy-2H-benzotriazol-2-yl)phenoxycarbonyl,2,5-dimethyl-4-(2H-benzotriazol-2-yl)phenoxycarbonyl,2,5-dimethyl-4-(5-chloro-2H-benzotriazol-2-yl)phenoxycarbonyl,2-methyl-4-(2H-benzotriazol-2-yl)phenoxycarbonyl,2-methyl-4-(5-chloro-2H-benzotriazol-2-yl)phenoxycarbonyl,2-chloro-4-(2H-benzotriazol-2-yl)phenoxycarbonyl,2,5-dichloro-4-(2H-benzotriazol-2-yl)phenoxycarbonyl,2-chloro-4-(5-chloro-2H-benzotriazol-2-yl)phenoxycarbonyl,2,6-dichloro-4-(5-chloro-2H-benzotriazol-2-yl)phenoxycarbonyl,2,6-dimethyl-4-(5-methoxy-2H-benzotriazol-2-yl)phenoxycarbonyl,2,6-dichloro-4-(5-methoxy-2H-benzotriazol-2-yl)phenoxycarbonyl,2-chloro-4-(5-methoxy-2H-benzotriazol-2-yl)phenoxycarbonyl,2-methyl-4-(5-methoxy-2H-benzotriazol-2-yl)phenoxycarbonyl,2-phenyl-4-(2H-benzotriazol-2-yl)phenoxycarbonyl,2-phenyl-4-(5-chloro-2H-benzotriazol-2-yl)phenoxycarbonyl,2-phenyl-4-(5-methoxy-2H-benzotriazol-2-yl)phenoxycarbonyl,4-(4,6-dichloro-2H-benzotriazol-2-yl)phenoxycarbonyl,4-(4,6-dimethyl-2H-benzotriazol-2-yl)phenoxycarbonyl, and the like.

Suitable C moieties having the formula ##SPC4##

are for example, phenyl, benzen-1,2-diyl, benzen-1,3-diyl,benzen-1,4-diyl, benzen-1,2,4-triyl, benzen-1,3,5-triyl,benzen-1,2,3-triyl, benzen-1,2,4,5-tetrayl, 4-cyanophenyl,2,4-dimethylphenyl, 3-methoxyphenyl, 2,4-dichlorophenyl,4-benzoylphenyl, 4-bromo-2-chlorophenyl, 2-bromobenzen-1,4-diyl,4-methoxybenzen-1,2-diyl, 2,5-difluorobenzen-1,4-diyl, 4-phenoxyphenyl,4-acetamidophenyl, (4-(2-benzoxazolyl)phenyl, and4-(2-benzthiazolyl)phenyl), 1,2-dinaphthoyl, 1,3-dinaphthoyl,1,4-dinaphthoyl, 1,5-dinaphthoyl, 1,6-dinaphthoyl, 1,7-dinaphthoyl,1,8-dinaphthoyl, 2,6-dinaphthoyl, 2,7-dinaphthoyl, 2,8-dinaphthoyl,5-methoxy-1,2-dinaphthoyl, 5-chloro-1,2-dinaphthoyl,6-methoxy-1,3-dinaphthoyl, 4-chloro-1,8-dinaphthoyl,6,7-dimethyl-1,4-dinaphthoyl, 8-methoxy-1,3-dinaphthoyl,1,2,5,6-tetranaphthoyl, 1,4,5,8-tetranaphthoyl, 2,4,6-trinaphthoyl,1,3,5-trinaphthoyl, and the like.

The polychromophoric compositions can be prepared by reacting an aroylchloride with a benzotriazole phenol. For example, one group of suchorganic compounds useful as ultraviolet stabilizers is, for example,compositions having the following structure ##SPC5##

One method for preparing these compounds is by the following procedure:##SPC6##

It is necessary that at least one carbon atom adjacent to the carbonatom attached to the carbonyl group contain a hydrogen substituent sothat on exposure to ultraviolet light, the aryl ester is capable by thephoto-Fries rearrangement of forming a phenol group in that positionformerly joined through an oxygen atom to the carbonyl linking group, asfor example: ##SPC7##

The heterocyclic compositions can be added to organic compositions whichare susceptible to ultraviolet degradation. Such compositions include,for example, polymeric compositions such as polyester fiber and moldingcompositions, such as polyethylene terephthalate, poly(tetramethyleneterephthalate) and the like; polyolefins such as, for example, high,medium and low density polyethylene, polypropylene, polybutene and thelike; polyamides such as nylon 6, nylon 66, N-methoxymethylpolyhexamethylene adipamide and the like; polycarbonates; polyvinylchlorides and copolymers; cellulose esters; acrylic/butadiene/styreneplastic; polyacrylics such as methyl methacrylate; polystyrene; gelatin;vinylidene chloride copolymers such as vinylidene chloride/vinyl acetatecopolymers; ethylene vinyl acetate copolymers; cellulose ethers such asmethyl cellulose; polyvinyl esters such as polyvinyl acetate;polyethylene oxide; polyvinyl acetals; polyformaldehydes; andpolyurethanes. Such compositions also include natural and syntheticrubbers, such as polybutadiene, and unsaturated organic compositionssuch as oils and the like, as well as compositions containing suchorganic compositions.

The polychromophoric compositions, as effective ultraviolet stabilizersor screening agents, are generally used in an amount of from 0.01 to10%, by weight, based on the weight of the organic material to whichthey are added. While a detectable amount of ultraviolet screening andstabilization may be obtained with amounts less than 0.01%, this amountof stabilization or screening would be of little practical utility in acommercial application. Moreover, while amounts greater than 10%, byweight, provide effective ultraviolet stability and screening, suchconcentrations are undesirable because of cost and the deleteriouseffect which such concentrations may have on the mechanical propertiesof the organic composition in which the stabilizer is incorporated.Preferably, the stabilizer is used in an amount of from about 0.1 toabout 3%, by weight. For example, an amount of 2%, by weight, of thestabilizer effectively stabilizes cellulose acetate butyrate andpolyester such as poly(tetramethylene terephthalate) plasticcompositions.

The ultraviolet stabilized organic compositions of the present inventionmay also contain other additives, pigments, colorants, stabilizers andthe like. For example, polymeric compositions, such as polyolefins, mayalso contain and generally do contain other additives such as white orcolored pigments or colorants, antioxidants, plasticizers, flow aids,processing aids, polymeric modifiers and the like.

These novel polychromophoric ultraviolet stabilizers may be incorporatedinto organic compositions by melt-blending or may be added onto thesurface of an organic plastic material prior to being molded into asuitable object. These materials can also be added to coatings and thelike which can be applied to the surface of a molded object.

This invention will be further illustrated by the following examplesalthough it will be understood that these examples are included merelyfor purposes of illustration and are not intended to limit the scope ofthe invention.

EXAMPLE 1

Preparation of p-(2H-benzotriazol-2-yl)phenylbenzoate (I) can beprepared by the following procedure:

o-Nitroaniline (0.5 mole) was diazotized in the usual manner withconcentrated hydrochloric acid (200 ml.) and sodium nitrite (0.5 mole).The clear diazonium solution was added slowly to a cold solution(0°-5°C.) of phenol (0.5 mole) in 450 ml. of 10% sodium hydroxide. Themixture was stirred for 1 hour and Compound A filtered out (60% yield).One-tenth mole of Compound A was dissolved in 100 ml. of 2N NaOH. Zincdust (30 g.) and sodium hydroxide (50 ml. of a 25% solution) were addedslowly to the well-stirred solution to keep the temperature below 45°C.The mixture was then cooled to <30°C. and acidified with concentratedhydrochloric acid. After stirring for 2 hours, the precipitate wasfiltered. Compound B was recrystallized from ethanol-water (m.p.216°-8°C., 90% yield). To the stirred solution of Compound B (0.02 mole)in 50 ml. of 1.6% sodium hydroxide, benzoyl chloride (0.02 mole) in 50ml. of chloroform was added slowly. The mixture was refluxed for 2hours. The organic layer was separated and washed with water. Afterremoval of chloroform by evaporation, compound (I) was obtained. Theproduct, I, was purified by crystallization from ethanol. (Yield: 80%,m.p. 164°-6°C.).

Anal. Calcd. for C₁₉ H₁₃ N₃ O₂ : C, 72.48 H, 4.27; N, 13,53. Found C,72.37; H, 4.16; N, 13.13. ##SPC8##

Other novel polychromophoric compounds can be prepared by substitutionof other benzotriazoles for 4-(2H-benzotriazol-2-yl)phenol, such as4-(5-chloro-2H-benzotriazol-2-yl)-2,5-dimethylphenol,4-(5-chloro-2H-benzotriazol-2-yl)phenol,4-(5-methyl-2H-benzotriazol-2-yl)-2,5-dimethylphenol,4-(5-methyl-2H-benzotriazol-2-yl)-2-methylphenol,4-(5-chloro-2H-benzotriazol-2-yl)-2-methylphenol,4-(2H-benzotriazol-2-yl)-2-methylphenol,4-(2H-benzotriazol-2-yl)-2-chlorophenol,4-(5-chloro-2H-benzotriazol-2-yl)-2-chlorophenol,4-(5-methyl-2H-benzotriazol-2-yl)-2-chlorophenol,4-(2H-benzotriazol-2-yl)-2,5-dimethoxyphenol,4-(5-chloro-2H-benzotriazol-2-yl)-2,5-dimethoxyphenol,4-(5-methyl-2H-benzotriazol-2-yl)-2,5-dimethoxyphenol,4-(2H-benzotriazol-2-yl)-2-methoxyphenol,4-(5-chloro-2H-benzotriazol-2-yl)-2-chlorophenol, and4-(5-methyl-2H-benzotriazol-2-yl)-2-methoxyphenol.

Also, other polychromophoric compounds can be prepared by substitutingother aroyl chlorides for benzoyl chloride such as 2,4-dichlorobenzoylchloride, 2,4-dimethoxybenzoyl chloride, 4-n-butoxybenzoyl chloride,terephthaloyl chloride, 3-cyanobenzoyl chloride, isophthaloyl chloride,1,3,5-benzenetricarboxylic acid chloride, phthaloyl chloride,2-bromoterephthaloyl chloride, 2,5-dimethoxyterephthaloyl chloride,4-(2-benzoxazolyl)benzoyl chloride and 4-(2-benzthiazoyl)benzoylchloride.

EXAMPLE 2

Bis-[p-(2H-benzotriazol-2-yl)phenyl]terephthalate (II) can be preparedby the reaction of p-(2H-benzotriazol-2-yl)phenol with terephthaloylchloride as in the procedure described for I, m.p. >300°C., yield 75%.

Anal. calcd. for C₃₂ H₂₀ N₆ O₄ : C, 68.32; H, 3.86; N, 15.09. Found: C,69.56; H, 3.65; N, 15.21.

EXAMPLE 3

Bis-[p-(2H-benzotriazol-2-yl)phenyl] isophthalate (III) can be preparedby reaction of p-(2H-benzotriazol-2-yl)phenol with isophthaloyl chlorideas in the procedure described for I, (m.p. 290°-2°C., yield 90%).

Anal. calcd. for C₃₂ H₂₀ N₆ O₄ ; C, 68.97; H, 3.95; N, 15.25. Found: C,69.56; H, 3.65; N, 15.21.

EXAMPLE 4

Tris-[p-(2H-benzotriazol-2-yl)phenyl] 1,3,5-benzenetricarboxylate (IV)can be prepared by reaction of p-(2H-benzotriazol-2-yl)phenol with1,3,5-benzenetricarboxylic acid chloride as in the procedure describedfor I, (m.p. 305°-310°C., yield, 80%).

Anal calcd. for C₄₅ H₂₇ N₉ O₆ ; C, 68.24; H 3,60; N, 15.52. Found: C,68.44; H, 3.45; N, 15.96.

EXAMPLE 5

The ultraviolet stabilization provided by the heterocyclic compound ofthe present invention is shown for poly(tetramethylene terephthalate) inTable 1.

A dry mixture of the stabilizer and granulated poly(tetramethyleneterephthalate) was extruded into one-sixteenth-inch diameter rods,pelletized and injection molded into 21/2 × 1/2 × 1/16-inch flat bars;these flat bars were exposed to a 280-700 nm. mercury lamp source.

The test results are summarized in Table 1.

                  Table 1                                                         ______________________________________                                        Effectiveness of Ultraviolet Stabilizers in                                   Poly(tetramethylene terephthalate)                                                        FWIS (Flatwise Impact Strength)                                   Compound (0.5%)                                                                             Initial   500 hr.    1000 hr.                                   ______________________________________                                        None          17         1          1                                         I             19        20         14                                         II            19        20         20                                         III           19        20         19                                         IV            19        20         18                                         ______________________________________                                    

These polychromophoric compositions find particular utility asultraviolet stabilizers in organic compositions requiring ultravioletstability. Such compositions include polymeric compositions such as, forexample, polyester fiber and molding compositions, poly-α-olefins,polyamides, acrylics, cellulose esters and the like, as well as moldedor shaped articles, film and coatings formed from such materials and thelike. Such compositions also include natural and synthetic rubbers, suchas natural rubber, as well as organic materials such as oils, fats, andunsaturated organic materials and materials having such materialscontained therein such as paints, varnishes, cosmetics and the like.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention.

We claim:
 1. An organic composition susceptible to ultraviolet lightdegradation stabilized against such degradation with a stabilizingamount of at least one compound having the formula:

    (A).sub.a --C

wherein A is a group having the structure ##SPC9## wherein the oxy groupis in the meta or para position to the benzotriazole group; R₁, r₂, r₃and R₄ are hydrogen, chloro, bromo, fluoro, lower alkyl, substitutedlower alkyl, cycloalkyl, substituted cycloalkyl, aryl, substituted aryl,lower alkylaryl, aryl-substituted-aryl, alkoxy, substituted amino,cyano, carboalkoxy and the substituents R₁ and R₂, R₂ and R₃, and R₃ andR₄, combined with the carbon atoms to which they are attached, arejoined alkylene groups completing a carbocyclic ring, which ring canalso be substituted with one or more of the substituents listed abovefor R₁, R₂, R₃ and R₄ ; I is the same as R₁, R₂, R₃ and R₄ and ispresent on all positions of the benzenoid ring, except the carbon atomattached to the heterocyclic ring and the carbon atom attached to thecarbonyl group connecting the heterocyclic aromatic A group with thearomatic C group, at least one I substituent on one of the carbon atomsadjacent to said carbon atoms attached to said carbonyl group ishydrogen and said remaining I substituents can all be the same ordifferent; a is an integer of 1 to 4; and C is an aromatic group havingthe formula: ##SPC10## where I is the same substituent as listed aboveand is present in all positions of the benzenoid ring except the carbonatom attached to the carbonyl group connecting the A and C moieties, andsaid I substituents can all be one of the substituents listed above ordifferent listed substituents.
 2. An organic composition according toclaim 1 containing a stabilizing amount of a composition of matterhaving the formula: ##SPC11##
 3. An organic composition according toclaim 1 containing a stabilizing amount of a composition of matterhaving the formula: ##SPC12##
 4. An organic composition according toclaim 1 containing a stabilizing amount of a composition of matterhaving the formula: ##SPC13##
 5. An organic composition according toclaim 1 containing a stabilizing amount of a composition of matterhaving the formula: ##SPC14##
 6. An organic composition according toclaim 1 containing a stabilizing amount of a composition of matterhaving the formula: ##SPC15##
 7. An organic composition according toclaim 1 containing a stabilizing amount of a composition of matterhaving the formula: ##SPC16##
 8. An organic composition according toclaim 1 containing a stabilizing amount of a composition of matterhaving the formula: ##SPC17##
 9. An organic composition according toclaim 1 containing a stabilizing amount of a composition of matterhaving the formula: ##SPC18##
 10. An organic composition according toclaim 1 containing a stabilizing amount of a composition of matterhaving the formula: ##SPC19##
 11. An organic composition susceptible toultraviolet degradation stabilized against such degradation with astabilizing amount of at least one compound according to claim 1 havingthe formula: ##SPC20##wherein the ester linking group is in the meta orpara position to the benzotriazole group; a is an integer of 2 to 4; R₁,r₂, r₃ and R₄ are hydrogen, chloro, bromo, lower alkyl, substitutedlower alkyl, cycloalkyl, substituted cycloalkyl, aryl, substituted aryl,lower alkylaryl, alkoxy, aryloxy, substituted amino, cyano, carboalkoxyand the substituents R₁ and R₂, R₂ and R₃, R₃ and R₄, combined with thecarbon atoms to which they are attached, are joined alkylene groupscompleting a carbocyclic ring, which ring can also be substituted withone or more of the substituents listed above for R₁, R₂, R₃ and R₄ ; Iis the same as R₁, R₂, R₃ and R₄ and is present on all positions of thebenzenoid ring, except the carbon atom attached to the carbonyl linkingsubstituent, at least one of said I substituents on one of the carbonatoms adjacent to said carbon atom attached to said carbonyl group ishydrogen and the remaining I substituents can all be one of thesubstituents listed above or different listed substituents.
 12. Anorganic composition according to claim 11 having the formula: ##SPC21##13. An organic composition according to claim 11 containing astabilizing amount of a composition of matter having the formula:##SPC22##
 14. An organic composition according to claim 11 containing astabilizing amount of a composition of matter having the formula:##SPC23##
 15. An organic composition according to claim 11 containing astabilizing amount of a composition of matter having the formula:##SPC24##
 16. An organic composition according to claim 11 containing astabilizing amount of a composition of matter having the formula:##SPC25##
 17. An organic composition according to claim 11 containing astabilizing amount of a composition of matter having the formula:##SPC26##
 18. An organic composition according to claim 11 containing astabilizing amount of a composition of matter having the formula:##SPC27##
 19. An organic composition according to claim 11 containing astabilizing amount of a composition of matter having the formula:##SPC28##
 20. An organic composition according to claim 11 containing astabilizing amount of a composition of matter having the formula:##SPC29##